Fix isSupportedToBuildEffective() propagation
InferredStatementContext has bad interaction with ImplictStmtCtx -- the
latter fizzles when it is not supported by features. This leads to a
failure to build effective context, as the prototype cannot be built and
therefore an attempt to reuse it fails.
Adjust InferredStatementContext to check if its prototype can be built
and carry over that fact when it is not.
JIRA: YANGTOOLS-1465
Change-Id: Iad05b0c6a06b6d9f837b70ced0da8cdc8ed3ed97
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>
(cherry picked from commit
e31531765d8ae6e3bc36f3de4ae4e14e06568e83)